1. Field of the Disclosure
The disclosure relates to a paint application device, in particular for the application of water-dilutable paints, where the term “paints” covers any kind of surface coating using in particular water-dilutable materials.
2. Description of the Prior Art
For instance for the purpose of coating elongated work pieces, such as boards and the like, it is known to apply paints, lacquers or the like on the surfaces by means of coating heads or spray heads, for example. A spray head, suitable in particular for the application of water-dilutable paints or coatings, is described in EP 10 162 699.2, for example. In this case, the paint is supplied into a chamber through which the work piece to be coated is passed. Excess coating material is withdrawn from the chamber, in which in particular a vacuum prevails, and is supplied to a paint reservoir. From the paint reservoir, the paint is supplied to the spray head again by a pump or the like. Although this is a substantially closed circuit, it cannot be avoided that a part of the solvent contained in the paint, such as water, evaporates thereby causing a change in the viscosity of the paint. Owing to this increase in viscosity, the paint becomes more viscous so that a uniform spraying of the paint in the spray head, and thus in particular an application of thin layers of paint and/or of exact application quantities, is no longer reliably ensured. Further, a clogging of the spray head and the like can occur. For this purpose it is known to supply a solvent to the paint reservoir by opening a valve. This is also the case with highly viscous paints. This is very troublesome and difficult, especially with water-dilutable paints, since the water often remains on the surface of the paint and mixing or stirring it into the same is troublesome.